At present, LCDs as the display components of electronic devices are widely used in various electronic products, and the backlight module is one of the essential components of the LCDs. As shown in FIG. 1, the existing LCD 10 comprises a frame 12, a LCD panel 14 assembled on the frame 12, and a backlight module 16; wherein the backlight module 16 comprises an optical diaphragm 161, a light guide plate 162, a lamp tube 163, a reflection sheet 164 and a backplane 165. The light guide plate 162 is arranged under the optical diaphragm 162 in a stacked mode; the lamp tube 163 is arranged on one side of the light guide plates 162; the reflection sheet 164 is arranged under the light guide plate 162 in a stacked mode; the backplane 165 is arranged under the reflection sheet 164; and the backplane 165 is in the structure of a buckle plate in accordance with the design requirements of the structure and function of the backlight module 16, and is partially in contact with the reflection sheet 164 to support the reflection sheet 164. Wherein, the reflection sheet 164 is used for reflecting the light emitted by the lamp tube 163 to the light guide plates 163. However, the reflection sheet 164 is easily affected by heat and then is softened to cause a large droop, particularly in the position close to a heat source, such as light beams, etc. The common solutions include adding reinforcing ribs 166 in the space between the reflection sheet 164 and the backplane 165, and the reflection sheet 164 is supported by the reinforcing ribs 166 (as shown in FIG. 1); or supporting bumps 167 are arranged on the backplane 165 (as shown in FIG. 2); or strips of adhesive tapes are applied on the bottom surface of the reflection sheet 164 (not shown in the figure). However, the addition of the reinforcing ribs 166 will obviously increase the cost of both the parts and the die, and also will increase the weight of the overall backlight module 16; the supporting bumps 167 will make the backplane become more complex, and increase the possibility of warp, and may cause other structural problems; the adhesive tape will increase the cost and bring trouble to the overall performance.